Electrical appliances such as dryers, heating, ventilating, and air conditioning (HVAC) units, and the like are well known in the art and understood to be commonplace in industrial and residential applications. The common HVAC unit or appliance configuration typically includes an access door or panel that mechanically interacts with a safety interlock switch. The safety interlock switch is depressed or activated when the access door or panel is in the closed position. In this case, the HVAC unit or electrical appliance is “hot” and electrical power is enabled. When the access door or panel is opened, the safety interlock switch is non-depressed (open) and deactivated. In the non-depressed (open) and deactivated position, the switch shuts off the electrical power to the HVAC unit or electrical appliance for safety and to avoid electrical shock. For a dryer or other electrical appliance, the safety interlock switch typically transitions to an open or deactivated position when the door is open, thereby preventing the dryer from starting when the door is open. For an HVAC unit, the access panel or door has a safety interlock switch that shuts down all power within the unit when the panel or door is open.
When the safety interlock switch is in the non-depressed (open) or deactivated position, a trained professional is unable to test the electrical components without electrical power to the HVAC unit or appliance. Common methods used by technicians for circumventing the purpose of the safety interlock switch is to tape over the switch or jam a small knife blade into the switch forcing it to remain in the depressed or activated position while the technician performs diagnostics. The circumvention of the safety interlock switch reconnects the electrical power to the HVAC unit or appliance facilitating hot testing and diagnosis. However, technicians often forget to remove the tape from the switch after the maintenance or repair is complete. The access door is closed over the tape and the switch is disabled, creating dangerous circumstances for the homeowner.
Most conventional HVAC units use a switching system to control various functions of the HVAC system, including the safety interlock switch. This switching system can be complicated when used or serviced in accordance with its standard operation and construction. The technician may also use a lock-out device, which works with a safety interlock switch to shut off the electricity and pneumatic power system during maintenance. Such a lock-out device can be cumbersome and too large to fit into a pocket. Another drawback of conventional interlock switch tools is that the mechanism usually requires the technician to use both hands to operate it.